In the art of conveying bulk material with conveyor belts, the belt is normally moved in a closed loop conveying path from the material pick-up station to a material discharge station. While moving along the conveying path, the underside of the central portion of the belt receives support from spaced idler rolls on the underside of the belt.
After the belt moves beyond the discharge station, the upper material supporting surface of the belt is moved in a lower or belt return path whereat it is also provided with support by idler rolls. These idler rolls on the return path contact the exterior surface of the belt which had previously been carrying the bulk material. Consequently, such return idler rolls have their exterior surfaces contacted by the materials remaining on the exterior surface of the belt whereby they may become abraded, soiled or receive other damaging effects. A recent advancement in improving the performance of this type of conveyor belt system is in the utilization of ceramic disks as the return idler. Such ceramic disks are superior to other disks in that they resist abrasion and soiling which would otherwise occur if another more conventional material were to be used in this area and for this function.
The use of ceramic disks as return idler rolls, however, creates other problems. Specifically, ceramic disks or disks of glass or other porcelain type ceramic materials or the like are brittle and not ductile and cannot be readily machined or formed to the dimensional tolerances of steel or other materials previously utilized. Ceramic disks must be extruded or cast and then fired or otherwise baked to create their hard, brittle, abrasion resistance and cleanable properties, properties desirable for the subject purpose.
Such ceramic disks, due to their method of fabrication, inherently have variations in their inside diameter. This causes a problem in coupling them to the metallic cylindrical shaft upon which they must be secured for functioning.
One such approach for coupling the ceramic disks to the shaft is disclosed in U.S. Pat. No. 3,847,260. In that case, as is well known commercially, tubular sleeves are employed for coupling ceramic disks to metallic shafts. Such sleeves include ribs or projections on one or more surfaces of the intermediate sleeves. These ribs deflect and resile when slidingly coupling the shaft to the disk. Deformation of the ribs of the sleeve during mounting permits the proper coupling of the disks to the shaft during functioning.